Pick-off mechanism



April 19, 1966 c DAVIS 3,246,799

PICK-OFF MECHANI SM Filed Dec. 15', 1963 2 Sheets-Sheet l April 19, 1966c. A. DAVIS 3,246,799

PICK-OFF MECHANISM Filed Dec. 13, 1963 2 Sheets-Sheet 2 FIG. 2

INVENTOR,

BY W 4.19am

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ATTORN EYS United States Patent 3,246,799 PICK-OFF MECHANISM Charles A.Davis, Saugus, Mass, assignor to W. J. Young Machinery (10., Inc., Lynn,Mass, a corporation of Massachusetts Filed Dec. 13, 1963, Ser. No.330,482 5 Claims. (Cl. 221-93) The present invention relates to a feedmechanism used primarily in connection with a nailing machine and moreparticularly, the present invention relates to an improved nail pick-offmechanism for a nailing machine feed mechanism, such, for example, asthe type shown in my United States Letters Patent 3,071,291 issuedJanuary l, 1963.

In Patent 3,071,291 an improved nailing machine feed mechanism isdisclosed. While the feed mechanism disclosed in that patent operateswith greater certainty and efiiciency than those heretofore known,occasional difiiculties have been encountered by nail jamming in theslots of the chutes leading from the nail hopper. In that construction,pick-off fingers or pawls function to secure the next to the lowermostnail in the chute while the lowermost nail drops from the chute asaresult of the pull of gravity. This operation is, however, somewhatuncertain because nails occasionally hang up at the bottom of chute orraceway.

It is therefore an object of this invention to provide an improved pawlor pick-off mechanism for a nailing machine feed mechanism which notonly firmly and securely holds a column of nails in a chute during theactuation of the mechanism of the type shown in'the aforementionedpatent, but also provides a positive downward force and feed for movingthe lowermost nail of the column from the chute or raceway to thenailing mechanism.

It is also an object of the present invention to provide an improvedfeed mechanismv for a nailing machine which is certain of operation overprolonged periods of time and which is relatively inexpensive tomaintain and repair.

A still further object of this invention is to provide a pawl and rackarrangement of improved design adapted for separating a leading nail ineach of several columns of nails from the columns themselves for furthermovement to the nailing machine, with the leading nail in each columnseparated with positive force from the column.

These and other objects and advantages of the present invention will bemore clearly understood from a consideration of the accompanyingdrawings in which:

FIGQl is a perspective view of the feed mechanism of a nailing machinewith the nailing machine shown in fragmentary form;

FIG. 2 is a plan' detail of an improved pawl and rack mechanism, andFIG. 2A is the mechanism shown in FIG. 2 at a subsequent point ofactuation.

The present invention may be embodied in the construction of 'nail feedmechanisms in general in which it is desirable to separate with apositive force, the lowermost nail of a column of nails contained withina downwardly extending chute. The invention also has application to. thefeed control of components having configurations similar to those ofnails, including for example, screws, rivets, pins, etc. But thepreferred embodiment of this invention is directed toward a constructionuseful in a nail feed mechanism of the type shown in United StatesLetters Patent 3,071,291.

The nail feed mechanisms with which the present invention may be used,may in turn be used in conjunction with various types of nailingmachines such as heel nailing machines. The nail feed mechanism may besup- Patented Apr. 19, 1966 ported on a frame 2, suitably secured in anyfashion to the machine 1. This frame preferably provides a horizontalflat surface. At the rear edge 20 of the frame there is secured by boltsor other suitable means, a support 3. This support 3 is formed withparallel opposed vertically extending legs 7 having enlarged upper endswith each end having fixed therein aligned journals 4. Axially supportedwithin these journals at its end is a shaft 5 having intermediate thejournals an enlarged center portion 9 with a series of parallel slots 21spaced apart and coincident with chutes 11, more completely describedhereinafter. The slots have a depth suflicient to accommodate the lengthof the nails 22 which are being fed through the feed mechanism and whichpass through these slots 21. The shaft 5 is adapted to be reciprocallyrotated about the axis of the shaft 5. The hopper 6 is rigidly securedto the shaft 5 and is adapted to be reciprocally rotated with it. Thishopper may be shaped and constructed to conform with the hopperillustrated in the foregoing patent. The hopper 6 may be reciprocallymoved from a horizontal position to the position illustrated in FIG. 1and then back to a horizontal position by conventional means. Thus, ifdesired, an actuating arm 42' pivotally engaging the lower surface ofthe bottom of the hopper and reciprocally moved from drive source (notshown), operating off a cam arrangement may be used to effect thisreciprocal movement of hopper 6. The hopper is provided with a series ofslots 42 in the bottom of the hopper with these slots parallel to oneanother and extending from the forward Wall 34 of the hopper rearwardly.

In the embodiment illustrated, seven such slots are provided eachaligned with one of the slots 21 in the sleeve 9. One of these slots isillustrated at 42 in dotted outline. These slots 42 have a widthsufiicient to receive the shanks but not the heads of nails containedwithin the hopper. Thus nails agitated by the rocking motion of thehopper will fall into the slots 42. These nails move forwardly due tothe rocking motion of the hopper towards the lower edge of the forwardwall 34. They pass through the slots illustrated at 43 in the forwardwall and drop into slots 21 in the section 9 which comprises a series ofchutes 11. It is desirable to utilize a gate mechanism generallyillustrated at 47 of the type described in the aforesaid patent,together with an adjustable plate 44 to control the feed of nails to thechutes without likelihood of jamming. The details of this arrangementmay be the same as in the aforesaid patent.

This reciprocating hopper 6 and gate mechanism 47 provide a constantflow of nails 22 into the slots 21. These nails slide from the slots 21into the chutes 11 in the raceway generally indicated at 10. Each of thechutes 11 is identical in arrangement with each chute aligned with aslot 21. The chutes are spaced one from another by spaces (not shown),which may comprise sleeves mounted on shafts secured at their ends atopposite sides of the outermost chutes by bolts or the like, asillustrated at 70. Each chute is formed with a U-shaped cross sectionproviding sliding walls 71, 72 spaced apart a distance coincident withthe width of slots 21. The channels 73 formed by these side walls extendthe full length of the chutes and are adapted to receive the nails 22 asthey slide downwardly from the slots 21.

The rear edges of the chutes 11 are arcuately curved to coincide andbear against portion 9 so as to present a smooth bearing surface to theshaft portion.

Intermediate the ends of the chutes l1 and toward the lower end of thechutes, there is provided means for simultaneously isolating thelowermost nail in each column of nails in the channels 73. This meanscomprises a series of pawls 75, with one pawl for each chute 11.. Thepawls 75 are pivotally mounted on a rack 76 which extends above andnormal to the length of the chutes 11. This rack 76 is mounted forlongitudinal reciprocal movement within the bearing blocks 77 andretainer plates 78. The rack 76 is actuated by the actuating arm 79projecting upwardly through the frame 2 and interconnected to the rack76 by means of a rod 80, fixed at one end to the arm 79 and pivotallyengaged in the other to the rack 76. This arm 79 may be positivelyactuated in one direction by a mechanism associated with the machine 1and timed to coincide with the desired operation of this machine. Thereturn mechanism for the arm 79 may comprise a helical spring 81 fixedat its ends between the supporting frame 83 on which the blocks 77 aremounted and the arm 79. Each pawl 75- is pivotally mounted to the rack76 by means of a pin 88, rigidly secured to the rack. Each pawl 75 isformed with a flat member lying substantially parallel to the rack 76.This fiat member comprises a hub 96 through which the pin 88 projects,and a finger 91. The finger is provided with a leading or forward edge92 having arcuate recess 93 at its end. The arcuate recess terminates atthe free end of the finger in a pointed wedge 94, with the other side ofthe wedge 94 being formed by the free end edge 95 of the finger. Thefinger 91 projects upwardly beyond the upper edge 96 of the rack 76,with the distance of projection to the pointed wedge 94 equaling thediameter of the nail heads normally used in the machine. The width ofthe finger may vary but the leading edge 92 should be preferably alignedwith a line passing tangentially through the column of nails on theright side thereof, as viewed in FIG. 2, when the rack is in its normalstatic position.

Each pawl has its pin 88 projecting beyond the outer surface of thepawl. A pin 98 also projects from this surface parallel to and spacedfrom the pin 88. A third pin 99 projects from the rack to a point beyondthe eX- posed or upper surface of the pawl 75. The pin 99 is positionedto engage the leading edge 92 of the pawl 75 so as to limit rotation ofthe pawl in a counterclockwise direction, as viewed in FIG. 2. Wiresprings 100 are looped about the pins 88 of each pawl and are providedwith two legs respectively engaging the opposite sides of pins 98 and 99of each pawl. These springs tension the pawls into rotating movementabout the pins 88 and towards the pins 99.

The pawls 75 are positioned immediately adjacent recesses 101, 101a inthe upper edge 96 of the rack 76, as illustrated in FIG. 2 the rack 76and recesses 101,101a are related and positioned such that recess 10111is positioned immediately to the right of the channel 73 shown in FIG. 2when the rack is not actuated by arm 79, as viewed in FIG. 1. In thisnon-actuated position, the lower surface of the rack 76 is in surfacecontact with the upper surface of the chutes 11. Thus, the lowermostnail in the column of nails 22 is engaged .by the upper edge 96 of therack 76 which prevents the lowermost nail 22 from moving furtherdownwardly in the chute. The lower end of each chute 11 is steppeddownwardly or recessed at a point 73a just under rack 76. Thus, as rack76 is moved to the left, as viewed in FIG. 2a, by the actuating arm 79,the lowermost nail in each column of nails will come into alignment witha recess 101a. The lowermost nail will be forced downwardly into therecess by the rearwardly projecting shoulder 94a of the pawl which movesto the left with the rack. On this movement the pointed wedge 94 andshoulder 94:; will be forced between the lowermost and next lowermostnail 22. The edge 95 will thereupon secure and support the column ofnails while the lowermost nail 22 is being forced downwardly. As therack continues to move toward the left, the downward pressure on thelowermost nail 22 is increased due to the increased tensioning of spring100, the force of which will be released when the lowermost nail 22becomes aligned with the recess 101a. As soon as this occurs thelowermost nail is forced downwardly into the recess 101a relieving thetension of springs 100. The nail forced into the recess will thereuponfall into the stepped portion of the chute, free of the rack 76. Thereleased nails will thereafter move downwardly past the rack 76 slidingdownwardly along the inclined chute 11 at the lower portions thereof,towards the forward edge of the chute. The secondmost nail in each chute11 is, however, retained in position above the rack 76 by engagementwith the pawl 75, as described above. As the rack 76 returns to itsinitial position by moving toward the right under tension of spring 81,the pawl 75 will be returned towards its initial position, thus movingaway from the nail that was originally second lowermost and therebyreleasing it to slide into contact with the upper edge 96 of the rack76.

A similar operation occurs in each channel. It will be noted, however,that each channel is individually opera tively controlled and thus ifjamming or diificulty occurs in one channel, it will not affectoperation in the other channels.

At the lower end of the raceway 10, there is provided a transport whichmay be of the type described in the aforementioned patent. The nails maythen be delivered in a known fashion from the channels by the transportto the nailing mechanism.

What is claimed is:

1. In a nailing machine feed mechanism having a plurality of parallelchutes each adapted to contain a column of nails with the heads of saidnails positioned on the upper surface of said chute and with areciprocally moving fiat bar forming an elongated rack extending acrosseach chute and positioned to engage the head of the lowermost nail ineach column when in a retaining position, said rack having release meansfor releasing said lowermost nail on lateral movement of said rack oversaid chute,

a device for retaining the second lowermost nail in each chute andsimultaneously forcing said lowermost nail downwardly on lateralmovement of said rack comprising,

a pawl for each chute, means pivotally mounting said pawls on saidracks, spring means for individually tensioning each pawl for rotationabout said mounting means in one direction, stop means for limiting therotation of said pawls in said direction, said pawls each having aforward edge terminating in a pointed wedge at the free end thereof, anarcuate recess formed in said forward edge immediately adjacent saidpointed wedge and positioned to engage the head of said lowermost nailon lateral movement of said rack, said pawl having a free end edgeprojecting beyond the upper edge of said bar for engagement of the headof said second lowermost nail on lateral movement of said rack, saidpointed wedge in the retaining position of said rack positioned abovesaid bar a distance equal to the diameter of the head of said lowermostnail whereby said pointed wedge is adapted on lateral movement of saidrack to move between said second lowermost and lowermost nails and incooperation with said arcuate recess and said free end edgesimultaneously retain all nails but the lowermost in said column andforce the lowermost downwardly from said column.

2. A device as set forth in claim 1 wherein said means for releasingsaid lowermost nail includes a recess for each chute extendingdownwardly from the upper edge of said bar with said arcuate recesses ofsaid of each pawls adapted to be pivoted against the tension of saidspring means while in engagement with said lowermost nails over saidrecesses on said lateral movement of said rack.

3. In a nailing machine feed mechanism having a plurality of parallelchutes each adapted to contain a column of nails with the heads of saidnails positioned on the upper surface of said chute and with areciprocally moving flat bar forming an elongated rack extending acrosseach chute and positioned to engage the head of the lowermost nail ineach column when in a retaining position, said rack having release meansfor releasing said lowermost nail on lateral movement of said rack oversaid chute,

a device for retaining the second lowermost nail in each chute andsimultaneously forcing said lowermost nail downwardly on lateralmovement of said rack comprising,

a pawl for each chute, means pivotally mounting said pawls on said rack,spring means for individually tensioning each pawl for rotation over alimited are in one direction, a pointed Wedge integral with each of saidpawls for separating said lowermost nail from said column and each ofsaid pawls also having a free end edge and arcuate recess forsimultaneously supporting the remainder of said column and forcing saidlowermost nail downwardly.

4. In a mechanism for controlling the individual feed of substantiallycylindrical elements retained parallel to one another in a column withina chute and having a release mechanism including a movable retainingrack extending transverse to said chute with release means at least inpart formed therein and adapted to be actuated on movement of said rack,the improvement comprising the combination of means for moving saidrack, means for separating the lowermost element from said column, meansfor simultaneously supporting the remainder of said column and means forsimultaneously exerting a positive downward force on said lowermostelement on movement of said rack.

5. The improvement as set forth in claim 4 wherein said means forseparating includes a pawl having a pointed wedge positioned to movebetween said lowermost element and said other elements with a secondportion of said pawl supporting said other elements.

References Cited by the Examiner UNITED STATES PATENTS 2,591,285 4/1952Overly 221-293 2,943,428 7/1960 Stroop 22l-93 3,071,291 1/1963 Davis22168 LOUIS J. DEMBO, Primary Examiner.

RAPHAEL M. LUPO, Examiner

4. IN A MECHANISM FOR CONTROLLING THE INDIVIDUAL FEED OF SUBSTANTIALLYCYLINDRICAL ELEMENTS RETAINED PARALLEL TO ONE ANOTHER IN A COLUMN WITHINA CHUTE AND HAVING A RELEASE MECHANISM INCLUDING A MOVABLE RETAININGRACK EXTENDING TRANSVERSE TO SAID CHUTE WITH RELEASE MEANS AT LEAST INPART FORMED THEREIN AND ADAPTED TO BE ACTUATED ON MOVEMENT OF SAID RACK,THE IMPROVEMENT COMPRISING THE COMBINATION OF MEANS FOR MOVING SAIDRACK, MEANS FOR SEPARATING THE LOWERMOST ELEMENT FROM SAID COLUMN, MEANSFOR SIMULTANEOUSLY SUPPORTING THE REMAINDER OF SAID COLUMN AND MEANS FORSIMULTANEOUSLY EXERTING A POSITIVE DOWNWARD FORCE ON SAID LOWERMOSTELEMENT ON MOVEMENT OF SAID RACK.